JPH085169A - Air conditioner - Google Patents

Abstract

PURPOSE:To prevent the level of the refrigerating machine oil of each compressor from being extremely uneven when all of a plurality of compressors operate or even when a part of a plurality of compressors stops. CONSTITUTION:An oil recovering circuit 26 is provided with ends communicating with the closed containers of compressors 10, 11 and 12, other ends communicating with inlet side pipelines 20, 21 and 22, an oil recovering and collecting pipeline 19 provided between both the ends and choke devices 16, 17 and 18 provided between the compressors 10, 11 and 12 and the oil recovering and collecting pipeline 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a plurality of compressors, and more particularly to an air conditioner in which refrigerating machine oil held by each compressor is equalized.

[0002]

2. Description of the Related Art In recent years, air conditioners have been made more space-saving due to improvements in living standards and workability, and there is an increasing demand for air conditioning of the entire building. A demand for a multi-room air conditioner including an outdoor unit provided and a plurality of indoor units has increased, and a design is made to equalize the refrigerating machine oil held by each compressor by using an oil equalizing pipe or the like.

As an air conditioner equipped with a plurality of conventional compressors to equalize the refrigerating machine oil held by each compressor, there is one disclosed in Japanese Utility Model Laid-Open No. 63-201964.

The above-mentioned conventional air conditioner will be described below with reference to the drawings. FIG. 11 is a refrigeration cycle diagram of a conventional air conditioner. In FIG. 11, 1 is a first compressor having a small capacity, 2 is a second compressor having a large capacity, and 3a and 3b, one of the first compressor 1 or the second compressor 2 is in operation and one is stopped. Check valve for preventing refrigerant from stagnation in the compressor on the stop side when the above occurs, 4 is an outdoor heat exchanger, 5
Is an accumulator, 6 is a main suction pipe for guiding the refrigerant from the accumulator 5 to the first compressor 1 and the second compressor 2, and 7 is a first
It is an oil equalizing pipe that equalizes the levels of refrigerating machine oil inside the closed containers of the compressor 1 and the second compressor 2.

Reference numerals 8a, 8b, 8c and 8d are pressure reducing devices having a fully-closed function, and 9a, 9b, 9c and 9d are indoor heat exchangers. Valve 3a,
3b, outdoor heat exchanger 4, pressure reducing devices 8a, 8b, 8c, 8
d, the indoor heat exchangers 9a, 9b, 9c, 9d, and the accumulator 5 are sequentially connected in an annular shape to form a refrigeration cycle.

The operation of the air conditioner configured as above will be described below. First, the refrigerant discharged from the first compressor 1 and the second compressor 2 is sent to the outdoor heat exchanger 4 through the check valves 3a and 3b. Pressure reducing device 8a, 8
The pressure is moderately reduced by b, 8c, and 8d, and the indoor heat exchanger 9
The refrigerant evaporated and gasified in a, 9b, 9c, 9d is returned to the first compressor 1 and the second compressor 2 through the accumulator 5.

Refrigerator oil is discharged from the compressors 1 and 2 together with the refrigerant, but circulates in the refrigeration cycle and returns to the compressors 1 and 2. The amount of oil discharged from the two compressors 1 and 2 is larger in the second compressor 2 having a larger capacity, but the level of the refrigerating machine oil inside can be made equal by the oil equalizing pipe 7.

[0008]

However, in the air conditioner of the above-mentioned conventional structure, when the two compressors 1 and 2 are simultaneously operated, the oil equalizing pipe 7 works to operate the two compressors 1 , 2 has the same refrigerating machine oil level.
When the indoor load is reduced, for example, the decompression devices 8c and 8d are fully closed, the first compressor 1 is stopped for capacity control, and only the second compressor 2 is operated. Since the pressure inside the compressor 2 is somewhat higher than the pressure inside the stopped first compressor 1, the refrigeration oil inside the second compressor 2 gradually accumulates inside the first compressor 1 and operates. There is a problem that the second compressor 2 being operated tends to run out of refrigerating machine oil. Further, the refrigerating machine oil is pushed into the cylinder of the stopped first compressor 1 through the oil supply pipe, and the first compressor 1
Had a problem of causing oil compression at the time of starting and causing the compressor to malfunction.

Further, in the above-mentioned conventional configuration, for example, in order to return the refrigerating machine oil accumulated in the refrigerating cycle to the compressors 1 and 2, the pressure reducing devices 8a, 8b, 8c and 8d are controlled to be fully opened. In this case, the amount of refrigerating machine oil that accumulates in the refrigeration cycle decreases, and the excess refrigerating machine oil rapidly returns to the closed containers of the compressors 1 and 2, and the refrigerating machine oil inside the closed containers of the compressors 1 and 2 is the maximum oil. There was a problem of reducing the compression function force beyond the surface.

Further, in the above-mentioned conventional configuration, the branch structure from the main suction pipe 6 to the suction side pipe 6a of the first compressor 1 and the suction side pipe 6b of the second compressor 2 does not cause refrigerant flow resistance. Since the structure is adopted and no particular device for distributing the refrigerating machine oil is made, the indoor load is reduced. For example, the pressure reducing devices 8c and 8d are fully closed,
When the capacity control operation is performed in which the first compressor 1 is stopped and only the second compressor 2 is operated, the suction side pipe 6 of the first compressor 1
When the refrigerant in a does not move and the suction side pipe 6a is located lower than the suction main pipe 6, refrigerating machine oil accumulates in the suction side pipe 6a and causes oil compression when the first compressor 1 is started. There were challenges. Further, when the suction main pipe 6 having a curvature is branched into the suction side pipe 6a and the suction side pipe 6b, the refrigerating machine oil flowing along the pipe inner wall surface of the suction main pipe 6 does not cover a part of the pipe inner wall surface of the suction main pipe 6. From the main suction pipe 6 to the suction side pipe 6a and the suction side pipe 6 while flowing uniformly.
It reaches the branching point with b, is distributed unevenly regardless of the intake gas amount ratio of the compressors 1 and 2, and the amount of refrigerating machine oil flowing into the first compressor 1 and the second compressor 2 becomes unbalanced, There is a problem that a difference easily occurs in the refrigerating machine oil levels of the compressors 1 and 2.

Furthermore, in the above-mentioned conventional structure, since the two compressors are connected by the oil equalizing pipe 7, the indoor load is reduced while the two compressors are in operation, and for example, the pressure reducing devices 8c and 8d.
Is fully closed, the first compressor 1 is stopped, and when the capacity control operation in which only the second compressor 2 is continuously operated is started, the inside of the first compressor 1 is Similarly to the above, since the substantially high pressure of the refrigeration cycle is maintained, even if the first compressor 1 is restarted due to an increase in indoor load, the operation of the second compressor 2 cannot be continued and once the first compressor 1 is restarted. 2 It is necessary to stop the compressor 2 and wait until the high and low pressures in the refrigeration cycle are balanced, and then start the first compressor 1 and the second compressor 2 again, during which air conditioning to the room is not possible. Had a problem.

In view of the above-mentioned problems, the present invention prevents refrigerating machine oil from accumulating in the stopped compressors when a part of a plurality of compressors is stopped, and the amount of refrigerating machine oil constantly accumulating in each compressor. Is equal to or less than the maximum oil level, and refrigerating machine oil is not accumulated in the suction side piping of the compressor in which some of the multiple units are stopped, and the distribution of the refrigerating machine oil to each compressor is equalized, In addition, when starting a compressor in which some of the multiple units are stopped, the stopped compressor can be started without stopping or reducing the capacity of other compressors that are running. The object is to provide an air conditioner that can follow.

[0013]

In order to achieve the above object, the air conditioner of the present invention according to the technical means described in claim 1 is a plurality of high pressure chamber type in which a discharge pressure acts in a closed container. A compressor connected in parallel, an outdoor heat exchanger, a decompression device, an indoor heat exchanger, and an accumulator are annularly connected via a refrigerant flow path to form a refrigeration cycle, and one end is Each of the compressors communicates with each closed container at a predetermined height between the oil supply limit oil level and the maximum oil level, and the other end communicates with the suction side pipe of each compressor, and
A collecting portion is provided in the middle of both ends, and an oil recovery circuit having a throttle device is provided between each compressor and the collecting portion.

In the air conditioner of the present invention according to the second aspect of the present invention, the operation of each compressor is performed by prioritizing the operation of the compressor having a preset high operation priority based on the air conditioning load on the indoor side. Of the plurality of compressors connected in parallel in a high-pressure chamber system in which a discharge pressure acts in a closed container. At least one, and
The compressor with the highest operation priority is a variable capacity compressor, and a plurality of compressors, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, and an accumulator are used as refrigerant flow paths. While forming a refrigeration cycle by annularly connecting via one end of each closed container at a predetermined height between the oil supply limit oil level and the maximum oil level of each compressor other than the variable capacity compressor Oil recovery circuit having a throttle device in the middle of both ends, and one end communicating with the suction side pipe of the variable capacity compressor, and one end having an oil supply limit oil level of the variable capacity compressor. And the maximum oil level communicate with the inside of the hermetically sealed container, the other end communicates with the suction side pipe of each compressor other than the variable capacity compressor, and gathers in the middle of both ends. Is provided between the suction side pipe of each compressor other than the variable capacity compressor and the collecting section. Those with other oil recovery circuit having a throttling device.

The air conditioner of the present invention according to the technical means as defined in claim 3 is provided with an oil sump tank between the variable capacity compressor and the collecting portion in another oil recovery circuit of the air conditioner. It is a thing.

According to the air conditioner of the present invention by the technical means described in claim 4, in the oil recovery circuit of the air conditioner described above, one end of the pipe connected to the closed container of each compressor is Between the oil level limit and the maximum oil level of the compressor,
And provided above the oil sump in the closed container of each compressor,
The oil recovery circuit is installed at a predetermined height below the oil level partition plate that separates oil from the discharge gas, and one end of the oil recovery circuit is projected into each of the closed containers.

The air conditioner of the present invention according to the technical means described in claim 5 is the air conditioner according to the technical means according to any one of claims 2 to 4, wherein the accumulator and the suction side pipe of each compressor are provided. And a suction side pipe of the compressor having the highest operation priority is connected to the most downstream part of the suction main pipe in the refrigerant flow direction.

The air conditioner of the present invention according to the technical means described in claim 6 is the air conditioner according to any one of the above-mentioned air conditioners, wherein the connection portion between the main suction pipe and the suction pipe of each compressor is connected. On the other hand, a projection is provided on the inner wall surface of the suction main pipe at the upstream side in the refrigerant flow direction.

The air conditioner of the present invention according to the technical means described in claim 7 is the air conditioner described in any one of claims 1 to 4, wherein the main suction pipe and the suction side pipe of each compressor are connected. A stirring tank for stirring the refrigerant and the oil in the suction main pipe is provided between, and one end of the suction main pipe is connected so as to be substantially tangential to the side wall surface of the stirring tank and substantially horizontal. The one end of the suction side pipe of each compressor is connected from the upper surface of the stirring tank.

The air conditioner of the present invention according to the technical means described in claim 8 is the air conditioner described in any of the above, wherein the main suction pipe is a closed container of each compressor and the suction of each compressor. Installed in a substantially horizontal direction below the connection position with the side pipe, at one end on the suction main pipe side of the suction side pipe of each of the compressors, in a substantially vertical upward direction with respect to the suction main pipe. An extended pipe extending portion is provided, one end of the oil recovery circuit on the suction side pipe side of each compressor is connected to the pipe extending portion, and the connecting portion is a closed container of each compressor and each of the compressors. It is arranged so as to be below the connection position with the suction side pipe.

The air conditioner of the present invention according to the technical means described in claim 9 is the air conditioner described in any one of claims 2 to 8, wherein the preset operation priority is based on the air conditioning load on the indoor side. A compressor operation control device that controls the operation of each compressor by giving priority to the operation of the compressor with the highest priority, an indoor load detection device that detects the air conditioning load on the indoor side, and a compressor with the highest operation priority And a check valve installed in the discharge side pipe of each compressor.

The air conditioner of the present invention according to the technical means described in claim 10 is the air conditioner according to any one of claims 2 to 9, wherein:
A compressor operation control device that controls the operation of each compressor by giving priority to the operation of a compressor having a high operation priority set in advance,
An indoor load detection device that detects the air conditioning load on the indoor side, a check valve installed in the discharge side piping of each compressor other than the compressor with the highest operation priority, and each check valve through an on-off valve. And a bypass circuit for bypassing the upstream side and the downstream side in the refrigerant flow direction of the compressor, and an on-off valve of the bypass circuit of the stopped compressor when it is detected that the compressor operating by the compressor operation controller is stopped. And a bypass control device that opens the valve for a predetermined time.

[0023]

In the air conditioner of the present invention configured as described above, since the oil recovery circuit that connects each compressor and the suction side pipe of each compressor is provided, all the plurality of compressors are operated. In this case, even if some of the compressors are stopped, the refrigerating machine oil level in each compressor can be adjusted without being extremely biased.

Further, since the oil recovery circuit for communicating the specific compressor with the suction side pipe of the specific compressor is provided, when all the plurality of compressors are operating, Even when a part of the compressor is stopped, the refrigerating machine oil level in each compressor can be adjusted without being extremely biased, and further, since the operation priority is high and the capacity is variable,
The surplus refrigerating machine oil of other compressors is preferentially supplied to the compressor where the fluctuation of the oil level is the largest, and the oil level is made uniform among the multiple compressors in a short time. Can be possible.

Further, since the oil sump tank is provided, when the amount of refrigerating machine oil accumulated in the refrigeration cycle decreases and the surplus refrigerating machine oil suddenly returns to the closed container of each compressor, the oil sump Refrigerating machine oil can be stored in the tank, and the refrigerating machine oil level inside the compressor closed container can be suppressed to the maximum oil level or less, and operation can be performed without lowering the compression function.

Further, since one end of the oil recovery circuit is projected to the inside of the compressor hermetic container below the oil level partition plate for separating the oil from the discharge gas, the refrigerating machine oil inside the compressor hermetic container is accumulated to a predetermined level. Since the refrigerating machine oil has never flown out of the compressor hermetically sealed container before, the refrigerating machine oil inside the compressor hermetically sealed container can be reliably stored at a predetermined level or higher.

Further, a part of the plurality of compressors is stopped by connecting the suction side pipe of the compressor having the highest operation priority to the most downstream part in the refrigerant flow direction of the suction main pipe. In this case, it is possible to prevent refrigerating machine oil flowing from the accumulator from accumulating in the suction side pipe of the compressor during stoppage and prevent oil compression from occurring at the time of starting the compressor during stoppage.

Further, by providing a protrusion on the inner wall surface of the main suction pipe, the refrigerating machine oil flowing along the inner wall surface of the main suction pipe is made to flow uniformly over the entire inner wall surface of the main pipe, and as a result, the amount of suction gas of each compressor According to the ratio, the amounts of refrigerating machine oil flowing into the respective compressors can be made substantially equal to reduce the occurrence of the difference in refrigerating machine oil levels of the respective compressors.

Further, by providing a stirring tank for stirring the refrigerant and the oil between the main suction pipe and the suction side pipe of each compressor, each compressor is provided with a stirring gas amount ratio. It is possible to equalize the amount of refrigerating machine oil that flows in and reduce the occurrence of a difference in refrigerating machine oil level between the compressors.

When a part of a plurality of compressors is stopped by setting the main suction pipe below the connection position between the closed container of each compressor and the suction side pipe of each compressor,
To prevent refrigerating machine oil flowing out to the suction side pipe of each compressor through the oil recovery circuit from accumulating in the suction side pipe of the compressor while stopped, and to cause oil compression when starting the compressor during stop. Can be prevented.

Further, by providing a check valve in the discharge side pipe of each compressor other than the compressor having the highest operation priority,
When starting a compressor in which some of the multiple units are stopped, the stopped compressor can be started without stopping other compressors in operation or reducing the capacity, and smooth load following can be performed. It can be possible.

Further, by providing a bypass circuit for bypassing the upstream side and the downstream side of each check valve in the refrigerant flow direction through the on-off valve, smooth load follow-up is enabled and a plurality of compressors are provided. When some of the compressors are stopped, the refrigerating machine oil level in each compressor can be adjusted without being extremely biased.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the air conditioner according to the present invention will be described below with reference to FIG. It should be noted that the same configurations as those of the related art are denoted by the same reference numerals and detailed description thereof will be omitted.

FIG. 1 is a refrigeration cycle diagram of the air conditioner in the first embodiment of the present invention. In FIG. 1, 1
0, 11, 12 are compressors, 13 is a first oil recovery passage of the compressor 10, 14 is a second oil recovery passage of the compressor 11, 15 is a third oil recovery passage of the compressor 12, 16, 17, 18 Is the first, second,
A throttling device, 19 disposed in the middle of each of the third oil recovery passages 13, 14, 15 is a first, second and third oil recovery passages 1.
It is an oil recovery collecting pipe that collects 3, 14 and 15.

20 is a suction side pipe from the suction main pipe 6 to the compressor 10, 21 is a suction side pipe from the suction main pipe 6 to the compressor 11, and 22 is a suction side pipe from the suction main pipe 6 to the compressor 12. , 23 from the oil recovery collecting pipe 19 to the compressor 10
Oil distribution passage communicating with the suction side pipe 20 of the compressor, reference numeral 24 represents an oil distribution passage communicating with the suction side pipe 21 of the compressor 11 from the oil recovery collecting pipe 19, and 25 represents the suction side pipe of the compressor 12 from the oil collecting collective pipe 19. It is an oil distribution path communicating with 22. The oil distribution passages 23, 24, 25 are designed so that the flow passage resistances are equal to each other.

26 is the first, second, and third oil recovery paths 13, 1.
4, 15 and the first, second and third oil recovery passages 13, 14, 1
Oil recovery collecting pipe 19 for collecting 5 and compressors 10 and 1
Suction side pipes 20, 21, 22, which are suction pipes for 1, 12
Is an oil recovery circuit composed of oil distribution paths 23, 24, 25 communicating with.

The first, second and third oil recovery passages 13, 14, 1
One end of 5 communicates with the inside of the compressor at a predetermined height between the limit oil level and the maximum oil level of the compressors 10, 11 and 12, and the other end communicates with the oil recovery collecting pipe 19. .

Here, the first, second and third oil recovery paths 13,
As the predetermined heights for communicating 14 and 15 with each other in the airtight containers of the compressor 10, the compressor 11 and the compressor 12, fluctuations during operation are added as margins to the respective oil supply limit oil level heights. Since the compressor oil is filled with refrigerating machine oil with a sufficient margin, the height is usually set to a position lower than the maximum oil level height. Further, the expansion devices 16, 17, and 18 are for maintaining the high pressure in each closed container during the operation of the compressor 10, the compressor 11, and the compressor 12.

The operation of the air conditioner configured as above will be described below. Compressors 10, 11, 12
Sucks in the gas refrigerant, compresses it, and discharges it as a high-temperature, high-pressure gas refrigerant into the closed container. At this time, the compressors 10, 1
Refrigerating machine oil for good lubrication sliding of the mechanical parts 1 and 12 is also discharged into the closed container at the same time, and part of it is discharged together with the refrigerant into the refrigeration cycle.

The refrigerating machine oil flowing out into the cycle circulates in the refrigerating cycle along with the flow of the refrigerant, and the accumulator 5
, And further from the accumulator 5 through the suction main pipe 6, the suction side pipes 20, 21, 22 to the respective compressors 1
It will return to 0, 11, and 12.

At this time, the method of returning the refrigerating machine oil circulating in the cycle to the compressors 10, 11, 12 is determined by the suction side pipes 20, 21, 2 of the respective compressors 10, 11, 12.
As a matter of course, a difference may occur depending on the length of 2 and the positional relationship with the main suction pipe 6.

In such a case, the oil level of the compressor returning a lot will be high, and the oil level of the compressor returning a small amount will be lowered.

Now, all the compressors 10, 11 and 12 are in operation, and there is sufficient refrigerating machine oil in the respective closed containers (the communication ports of the first, second and third oil recovery paths 13, 14, 15). If the oil level is higher than that), the pressure inside the closed container is approximately equal to the high pressure of the refrigeration cycle, so the refrigeration oil in each closed container has the first, second and third oil recovery paths 13, 1
It moves to the oil recovery collecting pipe 19 through 4, 15 and the respective compressors 10, 1 through the oil distribution paths 23, 24, 25.
1, 12 are guided to the suction side pipes 20, 21, 22 and returned to the compressors 10, 11, 12 and a sufficient oil level is maintained in each closed container.

Further, during the capacity control of the refrigeration cycle or during transient movement, for example, the oil level of the compressor 10 is not sufficient (the oil level is lower than the communication port of the first oil recovery passage 13). ) State, it is assumed that the oil level height of the compressors 11 and 12 is sufficient. That is, it is assumed that there is a difference in how the oil is returned to the compressors 10, 11, 12 during the process of circulating the refrigerating machine oil that has flowed out into the cycle.

At this time, from the compressor 10 to the first oil recovery passage 1
The oil is not taken out to the compressor 3, and the oil is supplied from the compressors 11 and 12 to the second and third oil recovery passages 14 and 15, and is supplied to the oil recovery collecting pipe 19.

The oil supplied to the oil recovery collecting pipe 19 is distributed according to the flow resistance of the oil distribution passages 23, 24, 25 and supplied to the suction side pipes 20, 21, 22 of each compressor.

The compressors 10, 11 and 12 suck in the gas refrigerant and at the same time suck in the distributed oil.
The oil level of 0 rises and works in a direction to correct to a sufficient state, and the oil levels of the compressors 11 and 12 gradually drop to work in a direction to correct to an appropriate oil level. , Compressor 10,
The operation of always maintaining the appropriate oil level heights of 11 and 12 is repeated, and the deviation of the oil level heights of the compressors 10, 11 and 12 can be prevented.

If the compressors 10, 11 and 12 have the same capacity, the oil distribution passages 23, 24 and 25 are designed to have the same flow resistance, and the oil to be distributed is divided into three equal parts.

When the capacities of the compressors 10, 11 and 12 are different, the larger the capacity of the compressor is, the larger the amount of suction gas is, so that the suction force to the suction side pipe becomes stronger.

For this reason, the amount of oil supplied from the oil recovery collecting pipe 19 to the oil distribution passages 23, 24, 25 is distributed according to the capacity of each compressor, so that compression with different capacities is performed. Obviously, it can also be applied to machines.

The operation when the oil level of the compressor 11 or the compressor 12 is not sufficient is the same as the above description.

Next, the indoor load is reduced during operation of the three compressors, for example, the pressure reducing devices 8c and 8d are fully closed, the compressors 10 and 11 are stopped, and only the compressor 12 is continuously operated. When the capacity control operation is started, the high-pressure gas refrigerant discharged from the compressor 12 flows to the outdoor heat exchanger 4,
Backflow into the closed containers of the compressors 10 and 11 that are stopped.

Therefore, the pressure inside the hermetically sealed containers of the compressors 10 and 11 is maintained at a high pressure, and the refrigerating machine oil inside the containers has a height of the oil level at which the first and second oil recovery paths 13 and 14 are connected. Until the first and second oil recovery passages 13 and 14, the suction side pipe 20,
It will be collected by the compressor 12 through the main suction pipe 6 via 21.

As described above, in the air conditioner of this embodiment, one end communicates with the compressor 10, 11, 12 in the compressor hermetic container at a predetermined height between the oil supply limit oil level and the maximum oil level. , The other end is the suction side pipes 20, 21, 22 of the compressors 10, 11, 12.
And an oil recovery collecting pipe 19 which is a collection part in the middle of the other end, and which has a throttle device 16, 17, 18 between the compressors 10, 11, 12 and the oil recovery collecting pipe 19. Since the circuit 26 is provided, the three compressors 10, 1
Not only during the operation of 1 and 12, but also when 1 unit is operating, 2 units are stopped, or 2 units are operating and 1 unit is stopped, the refrigerating machine oil level of the compressors 10, 11 and 12 is extremely high. It can be adjusted without bias.

In the present embodiment, the oil collecting and collecting pipe 19 at the collecting portion of the first, second and third oil collecting passages 13, 14 and 15 is used.
To the oil distribution passages 23, 2 of the suction side pipes 20, 21, 22
Although normal piping was used for Nos. 4 and 25 to equalize the flow path resistance, a combination with a distributor may be considered.

Next, a second embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 2 is a refrigeration cycle diagram of the air conditioner in the second embodiment of the present invention. In FIG. 2, 27
Is a variable capacity compressor, which can control the capacity by linearly changing the number of revolutions with an inverter or the like.

Reference numeral 28 denotes a first oil recovery circuit, which includes first and second oil recovery passages 13, 17 in which first expansion devices 16 and 17 are provided.
14 and an oil recovery collecting pipe 19 that collects the first and second oil recovery passages 13 and 14 and communicates with the suction side pipe 22 of the variable capacity compressor 27.

Reference numeral 29 is a second oil recovery circuit, which is the third oil recovery path 1
5, the first and second oil distribution passages 23 and 24, the compressor 10,
It is composed of 11 suction side pipes 20 and 21.

Further, the third oil recovery passage 15 has a first oil distribution passage 23 communicating with the suction side pipe 20 of the compressor 10 and a second oil distribution passage 24 communicating with the suction side pipe 21 of the compressor 11. , And the second diaphragm devices 18a and 18b.

Reference numeral 30 denotes a compressor operation control device for controlling the operation of each compressor by giving priority to the operation of a compressor having a high operation priority set in advance based on the air conditioning load of the indoor unit. It is a device that adjusts the number of operating compressors according to the magnitude of the air conditioning load detected by a device (not shown).

When the compressor operation control device 30 determines that the compressor needs to be operated, for example, when there is a command to start the heating operation from the remote controller or the like, the capacity of the operation priority is always the highest. When it is necessary to start the operation from the variable type compressor 27 and further add the compressor, the compressors 10 and 11 are appropriately added, and conversely, when the air conditioning load decreases and the compressor is stopped. , Compressors 10, 11
Is stopped first, and the variable capacity compressor 27 is stopped last.

This is because the variable capacity compressor 27 is used up to a certain air conditioning load in order to respond linearly to a fine air conditioning load.
When the air conditioning load exceeds the maximum capacity of the variable capacity compressor 27, either the compressor 10 or the compressor 11 and the variable capacity compressor 27 can be operated. If the air conditioning load further increases, the compressors 10 and 11 and the variable capacity compressor 27 are operated, so that the air conditioning load corresponding to the minimum capacity of the variable capacity compressor 27 changes from the air conditioning load to the compressors 10 and 11. And variable capacity compressor 2
It is possible to linearly correspond to the air conditioning load corresponding to the total capacity of the maximum capacity of 7.

The air-conditioning load detecting device detects whether the low pressure of the refrigeration cycle is high or low to judge the cooling load, and the high pressure of the refrigeration cycle is high or low to judge the heating load. is there. This is because if the capacity of the compressor is too small with respect to the cooling load, the low-pressure pressure of the refrigeration cycle rises, and conversely, if the capacity of the compressor is too large, the low-pressure pressure of the refrigeration cycle falls.

The same applies to the detection of the heating load.
If the capacity of the compressor is too small for the heating load, the high-pressure pressure in the cycle drops, and if the capacity of the compressor becomes too large, the high-pressure pressure in the cycle rises. It is widely used as a means.

The operation of the air conditioner configured as described above will be described below. The variable capacity compressor 27 is operated by the compressor operation control device 30 while linearly varying between the maximum capacity operation and the minimum capacity operation according to the air conditioning load on the indoor unit side.

Generally, the discharge amount of refrigerating machine oil of a compressor whose rotation speed is changed by an inverter or the like increases as the rotation speed increases, and conversely decreases as the rotation speed decreases. Therefore, the rotation speed is linearly changed. The fluctuation of the oil level of the variable capacity compressor 27 is larger than that of the other compressors 10 and 11.

Now, the indoor load detection device judges that the air conditioning load is maximum, and as a result, all the compressors are operated by the judgment of the compressor operation control device 30, in which the variable capacity compressor 27 When operating at maximum capacity, the oil level in the closed container of the variable capacity compressor 27 decreases. This is because the variable capacity compressor 27 is in the maximum operation and the discharge amount of the refrigerating machine oil is large.

In this case, the refrigerating machine oil above the connecting portions of the first and second oil recovery passages 13 and 14 in the hermetically sealed containers of the compressors 10 and 11 is the first and second refrigerating systems due to the high pressure of the refrigerating system. Since the variable capacity compressor 27 is supplied to the suction side piping 22 of the variable capacity compressor 27 through the two oil recovery paths 13 and 14 and the oil recovery collecting pipe 19, the variable capacity compressor 27 includes two compressors 10, 1.
Since the excess refrigerating machine oil No. 1 is collected, the oil level in the closed container can be secured even when the variable capacity compressor 27 is in maximum operation.

Further, when either the compressor 10 or the compressor 11 is stopped, the excess refrigerating machine oil of the stopped compressor is operated by the same operation as described above, and the variable capacity compressor is operated. It becomes possible to use as the refrigerating machine oil of No. 27, and it becomes easier to secure the oil level in the closed container even when the variable capacity compressor 27 is in the maximum operation.

On the other hand, when the variable capacity compressor 27 is operating at the minimum capacity, the discharge amount of refrigerating machine oil is smaller than that of the other compressors 10 and 11, so that the variable capacity compressor 2 is used.
The oil level height of 7 is higher than the oil level heights of the other compressors 10 and 11.

In this case, the second refrigeration circuit 29 causes the excess refrigerating machine oil of the variable capacity compressor 27 to move to another compressor 10,
11 and the compressors 10, 11 and the variable capacity compressor 27 operate in the direction of equalizing the oil level.

That is, the surplus refrigerating machine oil of the variable capacity compressor 27 is supplied to the compressor 10 via the expansion device 18a of the third oil recovery passage 15, the first oil distribution passage 23, and the suction side pipe 20. Similarly, the expansion device 1 for the third oil recovery passage 15
Since the oil is supplied to the compressor 11 via the 8b, the second oil distribution passage 24, and the suction side pipe 21, the oil level height of the variable capacity compressor 27 is reduced and the oil level heights of the compressors 10 and 11 are reduced. The higher oil level makes it possible to keep the balance of the entire oil level height constant.

Next, the indoor load is reduced, for example, the decompression devices 8c and 8d are fully closed, the compressor operation control device 30 stops the compressors 10 and 11, and the operation of only the variable capacity compressor 27 is continued. Then, even when the capacity control operation is started, the high-pressure gas refrigerant discharged from the variable capacity compressor 27 flows to the outdoor heat exchanger 4 while the stopped compressors 10, 11 are stopped. Back flow into the closed container of.

Therefore, the high pressure is maintained in the hermetically sealed containers of the compressors 10 and 11, and the refrigerating machine oil in the containers has a height of the oil level which is the height to which the first and second oil recovery passages 13 and 14 are connected. The first and second oil recovery passages 13 and 14, and the oil recovery collective pipe 1 until
9 through the suction side pipe 22 of the variable capacity compressor 27, and is collected by the variable capacity compressor 27.

Therefore, the absolute amount of refrigerating machine oil that can be used by the variable capacity compressor 27 is increased, and the variable capacity compressor 27 is increased.
It is possible to easily secure the required oil level even during the maximum operation of only one of the above.

As described above, the air conditioner of the present embodiment controls the operation of each compressor by giving priority to the operation of the compressor having a high operation priority set in advance based on the air conditioning load on the indoor side. Of a plurality of high-pressure chamber type compressors that include an operation control device 30 and an indoor load detection device that detects an air conditioning load on the indoor side, and discharge pressure acts in a closed container,
At least one compressor is a variable capacity compressor, and the compressor having the highest operation priority by setting the operation priority order is the variable capacity compressor 27.
0, 11, the outdoor heat exchanger 4, and the pressure reducing devices 8a, 8
b, 8c, 8d and indoor heat exchangers 9a, 9b, 9c,
9d and the accumulator 5 are annularly connected via a refrigerant flow path to form a refrigeration cycle. One end of the compressors 10, 11 other than the variable capacity compressor 27 communicates with the inside of the hermetically sealed container at a predetermined height between the oil supply limit oil level and the maximum oil level, and the other end of the variable capacity compressor 27. A first oil recovery circuit 28 that communicates with the suction side pipe 22 and has first expansion devices 16 and 17 in the middle of both ends, and one end of the variable capacity compressor 27 with the oil supply limit oil level and the maximum oil level. To communicate with the inside of the hermetically sealed container at a predetermined height, and the other end to communicate with the suction side pipes 20 and 21 of the compressors 10 and 11 other than the variable capacity compressor 27,
Moreover, an oil recovery collecting pipe 19 serving as a collecting portion is provided in the middle of both ends, and a second oil collecting collecting pipe 19 is provided between the suction side pipes 20 and 21 of the compressors 10 and 11 other than the variable capacity compressor 27 and the oil collecting collective pipe 19.
A second oil recovery circuit 29 having expansion devices 18a and 18b is provided. Therefore, not only during operation of the three compressors 10 and 11 and the variable capacity compressor 27, but also during operation of one of the two compressors or two of the compressors are stopped, Refrigerating machine oil level can be adjusted without being extremely biased.

Furthermore, since the excess refrigerating machine oil of another compressor can be preferentially supplied to the variable capacity compressor 27 having the largest fluctuation of the oil level, the variable capacity compressor 27
The oil surface height can be restored in a short time, and the oil surface heights of the three compressors can be made uniform.

Next, a third embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 3 is a refrigeration cycle diagram of the air conditioner in the third embodiment of the present invention. In FIG. 3, the second
The second embodiment is different from the embodiment described above in that the oil sump tank 31 is provided between the variable capacity compressor 27 and the second expansion devices 18a and 18b in the middle of the third oil recovery passage 15 to recover the second oil recovery. Circuit 29
Is the point that constitutes.

The operation of the air conditioner configured as above will be described below. Here, the difference from the operation of the second embodiment is that the refrigerating machine oil flowing out from the third oil recovery passage 15 communicating with the variable capacity compressor 27 is stored in the oil sump tank 3.
It is a point to temporarily store in 1.

In general, the amount of refrigerating machine oil enclosed in the refrigerating system is a sufficient amount that does not become insufficient even under each environmental condition where the device is installed and each operating state of the indoor unit.

Therefore, the amount of refrigerating machine oil accumulated in the refrigerating cycle decreases depending on the specific environmental conditions and the operating state of the indoor unit, and the surplus refrigerating machine oil is compressed into the compressors 10, 1.
Returning to Nos. 1 and 27, the oil may accumulate in the compressor closed container, and the oil level of the refrigerator inside the compressor closed container may exceed the maximum oil level.

For example, when three of the four indoor units are stopped and the depressurizing devices 8a, 8b, 8c are closed, the compressor 1 is judged by the compressor operation control device 30.
It is assumed that 0 and 11 are stopped and the variable capacity compressor 27 is operated at the minimum capacity.

In this case, since the amount of the refrigerant circulating in the refrigeration cycle is small, the flow velocity of the refrigerant becomes slow, and the refrigerating machine oil discharged into the system is difficult to circulate, that is, the connecting pipe to the indoor unit and the outdoor side. It adheres to frozen parts such as heat exchangers and stays there.

However, the compressors 10 and 11 that are stopped
The excess refrigerating machine oil in the closed container is collected by the variable capacity compressor 27 as described in the second embodiment, and the proper oil level of the variable capacity compressor 27 is secured.

From this state, if the air-conditioning load increases and one more indoor unit is operated, the decompression device 8a opens, the amount of refrigerant circulating through the system also increases, and the connecting pipe to the indoor unit and the outdoor side When the refrigerating machine oil attached to the refrigerating parts such as the heat exchanger starts to circulate, and further, in order to return the refrigerating machine oil accumulated in the refrigeration cycle to each compressor, the pressure reducing device 8a, When the control operation for forcibly fully opening 8b, 8c, 8d is performed, the variable capacity type that secures an appropriate oil level by receiving the supply of the excess refrigerating machine oil of the stopped compressors 10, 11 The oil level of the compressor 27 becomes abnormally high. At this time, the refrigerating machine oil that has returned excessively from the refrigeration cycle is supplied to the oil sump tank 31 via the third oil recovery passage 15 of the variable capacity compressor 27, so that the excess refrigerating machine oil is temporarily removed. It can be stored in the storage tank 31, the oil level of the refrigerating machine oil of the variable capacity compressor 27 can be maintained at a predetermined value, and the reduction of the compression function of the variable capacity compressor 27 can be prevented. .

As described above, in the air conditioner of the present embodiment, in the second oil recovery circuit 29, in the middle of the third oil recovery path 15, the variable capacity compressor 27 and the second expansion devices 18a and 18a are provided.
Since the oil sump tank 31 is provided between b, the excess refrigerating machine oil can be temporarily stored in the oil sump tank 31 even when the refrigerating machine oil returns excessively. The oil level height of the refrigerating machine oil can be maintained below the maximum oil level, and the reduction of the compression function force of the variable capacity compressor 27 can be prevented.

Next, a fourth embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 4 is a sectional view showing the internal structure of the compressor hermetic container of the air conditioner according to the fourth embodiment of the present invention.
Here, the compressor 10 of the first embodiment will be described as an example.

In FIG. 4, the difference from the first embodiment is that in the oil recovery circuit 26, the compressor 10 is provided with a discharge side pipe 32, and one end of the oil recovery passage 13 has an oil separating the oil from the discharge gas. The point is that it is installed below the surface partition plate 33 and between the oil supply limit oil level and the maximum oil level in the hermetic container 34 of the compressor 10 and protrudes into the hermetic container 34.

Reference numeral 35 denotes an oil sump, x denotes an oil supply limit oil level which is the minimum lower limit necessary for the compressor to supply refrigerating machine oil to the mechanical portion of the compressor, and the oil level partition plate 33 is a closed container 34. It is provided above the internal oil sump 35 and separates the discharge gas refrigerant inside the closed container 34 and the refrigerating machine oil.

The operation of the air conditioner configured as above will be described below. Here, the difference from the operation of the first embodiment is that the gas discharged from the compressor 10 is once discharged as a high-temperature and high-pressure gas containing refrigerating machine oil in the closed container 34, and the discharged gas is an oil level partition. This is the point at which the refrigerating machine oil separated into the refrigerant and the refrigerating machine oil by the plate 33 and separated and stored in the oil sump 35 to a predetermined level or more flows out through the oil recovery passage 13 protruding into the closed container 34.

Now, the gas discharged from the compressor 10 is once discharged as a high-temperature and high-pressure gas containing refrigerating machine oil in the closed container 34, and comes into contact with the wall surface, the motor, the mechanical section, etc. in the closed container 34, Refrigerating machine oil is separated and drops along the wall surface or drops directly from the motor, machine parts, etc.

This refrigerating machine oil is further dripped below the oil level partition plate 33 and stored in the oil sump 35.

The oil level of the refrigerating machine oil accumulated in the oil sump 35 is lower than one end of the first oil recovery passage 13 and one end of the first oil recovery passage 13 is flush with the inner wall surface of the closed container 34. When connected, the refrigerating machine oil falling along the wall surface is sucked into the first oil recovery passage 13 and taken out of the closed container on the way, and the oil reaches a predetermined oil level. It is expected that the oil will not accumulate and will fall below the refueling limit oil level x.

Therefore, in the air conditioner of the present embodiment, the first oil recovery passage 13 communicating with the inside of the closed container 34 is above the oil supply limit oil level x of the compressor 10 and below the oil level partition plate 33. Is installed at a predetermined height, and one end of the first oil recovery passage 13 is projected from the inner wall surface of the closed container 34 by a predetermined length. Therefore, the wall surface of the closed container 34 passes through the first oil recovery passage 13. Refrigerating machine oil flowing through the first oil recovery passage 13
Since it does not directly touch the open end of the, it will not be sucked out from this open end and flow out to the outside.

As described above, in the air conditioner of this embodiment, one end of the pipe connected to the closed container 34 in the first oil recovery passage 13 has the oil supply limit oil level x of each compressor and the oil in the discharge gas. Is installed at a predetermined height from the oil surface partition plate 33 that separates the oil, and one end of the first oil recovery passage projects into each closed container. Even in the case of the connection part of the passage 13 or less, the refrigerating machine oil propagating on the inner wall surface of the closed container 34 does not flow out to the outside, and the oil level can be maintained at a predetermined level. Can be reliably prevented.

Next, a fifth embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 5 is a refrigeration cycle diagram of an air conditioner according to a fifth embodiment of the present invention, and the second embodiment will be described as an example.

In FIG. 5, the difference from the second embodiment is that the accumulator 5 and the suction side pipes 20 and 2 of each compressor are different.
This is a point in which the suction main pipe 6 communicating with 1 and 22 is provided, and the suction side pipe 22 of the compressor 27a having the highest operation priority is connected to the most downstream part of the suction main pipe 6 in the refrigerant flow direction.

The operation of the air conditioner configured as described above will be described below. Here, the operation of the fifth embodiment is substantially the same as the operation of the second embodiment, so detailed description will be omitted.

Here, the compressor 2 having the highest operation priority
7a is operated at all times when the indoor unit is operating, as determined by the compressor operation control device 30, but the compressor 1
0 and 11 are repeatedly operated or stopped depending on the air conditioning load of the indoor unit.

Now, the air conditioning load is large, and all the compressors 10,
11 and when the compressor 27a is in operation, the gas refrigerant circulating from the accumulator 5 and the refrigerating machine oil circulating in the refrigeration cycle and returned from the suction main pipe 6 are suction side pipes 20, 21, 22 respectively. And the refrigerating machine oil supplied from the first oil collecting circuit 28 and the second oil collecting circuit 29 are sucked into the respective compressor hermetically sealed containers to be sucked into the suction main pipe 6 and the suction side pipes 20, 21, 22. It does not stay. However, when the air conditioning load becomes small and, for example, the compressors 10 and 11 stop, the second oil recovery circuit 29
Since the refrigerating machine oil supplied from the compressors 10 and 11 to the suction side pipes 20 and 21 is not sucked into the compressors 10 and 11, the refrigerating machine oil stays in the suction side pipes 20 and 21.

From this state, when the air conditioning load increases again and the compressor 10 or the compressor 11 is to be operated again, the refrigerating machine oil accumulated in the suction side pipe 20 or the suction side pipe 21 should be temporarily sucked. And, by oil compression,
There is a problem of damaging the compressor.

Therefore, in this embodiment, the suction side pipe 22 of the compressor 27a having the highest operation priority is connected to the suction main pipe 6
Since it is connected to the most downstream side in the refrigerant flow direction of the compressor 1,
0 and 11 are stopped and the compressor 1 from the second oil recovery circuit 29
Even if the refrigerating machine oil supplied to the suction side pipes 20 and 21 of 0 and 11 is no longer sucked into the compressors 10 and 11, the refrigerating machine oil supplied to the suction side pipes 20 and 21 is the first compressor 2
Due to the effect of suction of No. 7, it is once returned to the main suction pipe 6 and is sucked into the compressor 27 a through the suction side pipe 22.

Therefore, even when the compressor 10 or the compressor 11 is stopped, the refrigerating machine oil does not stay in the respective suction side pipes 20 and 21, and the air conditioning load increases, so that the compressor 10 or 11 is not cooled. It is possible to prevent oil compression even during re-operation.

As described above, since the suction side pipe of the compressor having the highest operation priority is connected to the most downstream part in the refrigerant flow direction of the suction main pipe, a part of the plurality of compressors is Even when the compressor is stopped, it is necessary to prevent the refrigerating machine oil flowing from the accumulator from accumulating in the suction side pipe of the stopped compressor, and to prevent oil compression when restarting the stopped compressor. You can

Next, a sixth embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 6 is a detailed view of the main parts of the suction side pipe of the compressor in the air conditioner of the sixth embodiment of the present invention, and the first embodiment will be described as an example.

In FIG. 6, the difference from the first embodiment lies in the connection between the suction main pipe 6 coming out of the accumulator 5 and the suction side pipes 20, 21, 22 of the compressors 10, 11, 12, respectively. The point is that a ring-shaped projection 36 is provided on the inner wall surface of the suction main pipe 6 on the upstream side in the refrigerant flow direction, substantially perpendicular to the refrigerant flow direction.

The operation of the air conditioner configured as described above will be described below. Here, the operation of the sixth embodiment is substantially the same as the operation of the first embodiment, so detailed description thereof will be omitted.

Now, the flow of the refrigerant in the air conditioner is discharged from the compressors 10, 11, 12 and passes through the indoor unit, the accumulator 5 and the suction main pipe 6, and then the compressors 10, 11, 1.
Returning to step 2, at this time, the action direction of the shearing force, which is generated at the boundary between the refrigerant flowing at high speed and the refrigerating machine oil flowing at low speed inside the main suction pipe 6 and becomes the refrigerating machine oil propulsive force, is usually By providing a ring-shaped projection 36 on the inner wall surface of the suction main pipe 6 substantially perpendicular to the refrigerant flow direction, the ring-shaped projection 36 acts on the flow resistance of the refrigeration oil in the refrigerant flow direction. Therefore, the shearing force also acts in a direction substantially perpendicular to the flow direction of the refrigerant. Therefore, the refrigerating machine oil that flows non-uniformly in a portion of the suction main pipe 6 collides with the ring-shaped projection 36, and the direction of the shearing force acting on the refrigerating machine oil is the same as that of the projection 36 with respect to the refrigerant flow direction. It also works almost vertically, and the entire ring-shaped projection 36 is covered with refrigerating machine oil, and the refrigerating machine oil that has been settled on the projection wall surface on the upstream side of the refrigerant flow is accumulated above the projection height in the refrigerant flow direction. Since it flows out, the refrigerating machine oil that flows non-uniformly in a part of the inside of the suction main pipe 6 quickly flows uniformly in the whole pipe. Therefore, each compressor 10, 11, 12
It is possible to reduce the imbalance in the amount of refrigerating machine oil flowing into the compressor and reduce the difference in refrigerating machine oil level between the compressors 10, 11, and 12.

Since the ring-shaped projection 36 provided on the main intake pipe 6 does not greatly block the cross-sectional area of the main intake pipe 6 in the direction of flow of the refrigerant, it does not become a resistance to the refrigerant, and therefore the air conditioning is performed. It does not affect the ability of the machine.

Furthermore, the compressor 1 communicating with the suction main pipe 6
Since the suction side pipes 20, 21, 22 of 0, 11, 12 do not have a structure protruding to the suction main pipe 6, refrigerating machine oil is prevented from flowing out to the suction side pipes 20, 21, 22 of the compressors 10, 11, 12. There is nothing to do.

Next, a seventh embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 7 is a detailed view of the main part of the suction side pipe of the compressor in the air conditioner of the seventh embodiment of the present invention, and the first embodiment will be described as an example.

In FIG. 7, the difference from the first embodiment is that a refrigerant is provided between the suction main pipe 6 communicating with the accumulator 5 and the suction side pipes 20, 21, 22 of the compressors 10, 11, 12. A stirring tank 37 for stirring the refrigerating machine oil is provided, and one end of the main suction pipe 6 is connected so as to be substantially horizontal in the tangential direction of the side wall surface of the stirring tank 37.
The point is that one ends of the suction side pipes 20, 21, 22 of 1, 12 are connected to the upper part of the stirring tank 37.

The operation of the air conditioner configured as described above will be described below. Here, the operation of the seventh embodiment is substantially the same as the operation of the first embodiment, so detailed description will be omitted.

Now, the refrigerant flow of the air conditioner is discharged from the compressors 10, 11, 12 and passes through the indoor unit, exits the accumulator 5, passes through the suction main pipe 6, and passes through the compressors 10, 1.
Returning to 1 and 12, at this time, the refrigerating machine oil is generated while receiving the shearing force which is generated at the boundary surface between the refrigerant flowing at a high speed and the refrigerating machine oil flowing at a low speed inside the suction main pipe 6 and becomes the refrigerating machine oil propulsive force. It flows along the inner wall surface of the pipe.

Therefore, by connecting one end of the main suction pipe 6 to be substantially horizontal in the tangential direction of the side wall surface of the stirring tank 37, the refrigerant flowing into the stirring tank 37 is
Since the inside of the stirring tank 37 swirls and flows, the refrigerating machine oil that has flowed into the stirring tank 37 is also stirred in the same manner.
It swirls inside and flows. In addition, each compressor 10,1
The suction side pipes 20, 21 and 22 of 1, 12 are connected to the stirring tank 3
By connecting to the upper part of 7, each compressor 10, 11,
As a result of the refrigerant being sucked by the suction side pipes 20, 21, 22 of 12, the refrigerant flow inside the stirring tank 37 is directed to the upper part of the stirring tank 37 while maintaining the swirl flow when flowing into the stirring tank 37. It becomes a flow with nature.

Therefore, the flow of the refrigerating machine oil inside the stirring tank 37 is also drawn to the upper part of the stirring tank 37 while swirling inside the stirring tank 37, and the compressors 10, 11,
The flow reaches twelve suction side pipes 20, 21, 22.

Therefore, the suction side pipes 20, 21, 22 of the compressors 10, 11, 12 are transmitted along the inner wall surface of the stirring tank 37.
Since the refrigerating machine oil reaching the above-mentioned section evenly flows on the inner wall surface of the stirring tank 37, the refrigerating machine oil amount flowing into each of the compressors 10, 11, 12 becomes equal, and the refrigerating machine oil level of each of the compressors 10, 11, 12 becomes equal. It is possible to reduce the occurrence of disparity.

Even when the compressor 10 is stopped, the refrigerant containing the refrigerating machine oil does not accumulate in the suction side pipe 20 of the stopped compressor 10, and the problem of liquid compression at the start is eliminated.

Furthermore, the suction side pipes 20, 21, 2 of the compressors 10, 11, 12 each having one end connected to the stirring tank 37.
Since No. 2 does not project into the stirring tank 37, refrigerating machine oil flows from the suction main pipe 6 into each of the compressors 10, 11,
It does not hinder the outflow into the 12 suction side pipes 20, 21, 22.

Next, an eighth embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 8 is a detailed view of the main part of the suction side pipe of the compressor in the air conditioner of the eighth embodiment of the present invention, and the first embodiment will be described as an example.

In FIG. 8, the main suction pipe 6 differs from the first embodiment in that the main suction pipe 6 is a closed container of each compressor 10, 11, 12 and the suction side pipes 20, 2 of each compressor 10, 11, 12.
It is installed below the connection position with 1, 2 and in a substantially horizontal direction. Further, at one end of the suction side pipes 20, 21, 22 of each of the compressors 10, 11, 12 on the suction main pipe 6 side, a suction side pipe extending portion 20a extending upward in a direction substantially perpendicular to the suction main pipe 6 is provided. 21a, 22a are provided, and the suction side pipe 2 of each compressor 10, 11, 12 in the oil recovery circuit 26 is provided.
One end on the 0, 21, 22 side is the pipe extending portions 20a, 21a,
22a, and the connecting portion of each compressor 10, 1
1, 12 closed containers and suction side pipes 20, 2 of each compressor
It is arranged so as to be lower than the connection position with the terminals 1 and 22.

The operation of the air conditioner configured as above will be described below. Here, the operation of the eighth embodiment is substantially the same as the operation of the first embodiment, so detailed description will be omitted.

Now, the refrigerant flow of the air conditioner is discharged from each of the compressors 10, 11, 12 and passes through the indoor unit, exits the accumulator 5, passes through the intake main pipe 6, and passes through each of the compressors 10, 11.
Returning to 11 and 12, however, a plurality of compressors 10 and 1
Even when some of the compressors 10 in 1 and 12 are stopped, the refrigerating machine oil flowing into the suction side pipe 20 of the compressor 10 stopped through the oil recovery passages 13, 14 and 15 is not stopped. Since there is no refrigerant flow to the compressor 10, no force acts on the refrigerating machine oil from the refrigerant. As a result, the refrigerant is not attracted to the stopped compressor 10 and flows through the intake side pipe 20 into the intake main pipe 6 for operation. It is sucked into the compressors 11 and 12 inside. Therefore, the refrigerating machine oil does not accumulate in the suction side pipe 20 of the compressor 10 in the stopped state, and there is no problem in the liquid compression at the start of the stopped compressor 10.

In the above description, it is assumed that one compressor is stopped, but the same operation is performed and the same effect can be obtained even when the number of compressors is two.

Next, a ninth embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 9 is a refrigeration cycle diagram of an air conditioner according to the ninth embodiment of the present invention, and the second embodiment will be described as an example.

In FIG. 9, the difference from the second embodiment is that the operation of each compressor is controlled by giving priority to the operation of the compressor having a high operation priority set in advance, based on the air conditioning load on the indoor side. A machine operation control device 30, an indoor load detection device for detecting an air conditioning load on the indoor side, and a check valve 38 installed in the discharge side pipes of the compressors 10 and 11 other than the compressor 27 having the highest operation priority. And 39.

The operation of the air conditioner configured as described above will be described below. Here, the operation of the ninth embodiment is substantially the same as the operation of the second embodiment, and detailed description thereof will be omitted.

Now, while the three compressors are in operation, the indoor load is reduced and, for example, the decompression devices 8b, 8c, 8d are fully closed,
When the compressors 10 and 11 are stopped and the capacity control operation of continuing the operation of the compressor 27 is started, the discharge gas of the compressor 27 flows backward to the discharge pipe side of the compressors 10 and 11,
It will be condensed in the closed container 11 and will become a liquid refrigerant and will stay.

Therefore, if the amount of condensed refrigerant is large, the amount of refrigerant circulated in the refrigeration cycle will be insufficient, and there will be a problem that comfortable air conditioning cannot be performed.

Therefore, in the air conditioner of this embodiment, the compressors 10 and 11 other than the compressor 27 having the highest operation priority are used.
Since check valves 38 and 39 are provided in the discharge side pipe of
The indoor load decreased during operation of one compressor, for example, the decompression devices 8b, 8c, 8d were fully closed, the compressors 10 and 11 were stopped, and the capacity control operation in which the compressor 27 was continued was entered. In this case, the discharge gas of the compressor 27 is
Will flow back to the discharge pipe side of the compressor 10,1
The check valves 38 and 39 provided in the middle of the first discharge pipe can prevent the reverse flow of the refrigerant.

Further, since the closed containers of the stopped compressors 10 and 11 are communicated with the main suction pipe 6 having a low pressure in the refrigeration cycle by the oil recovery paths 13 and 14, the stopped compressors 10 and 11 are stopped. Until the pressure inside the closed container becomes substantially equal to the low pressure of the refrigeration cycle, the refrigerating machine oil moves through the oil recovery paths 13 and 14 while being pushed by the internal pressure. When the inside of the hermetically sealed containers of the compressors 10 and 11 is maintained in a state where the pressure is substantially equal to the low pressure of the cycle,
Suction side pipes 20 and 21 and the discharge side compressors 10 and 1
The inside of the closed container 1 is in a pressure-balanced state.

Therefore, if the indoor load further increases from such a state and the pressure reducing devices 8b and 8c start to open, and the operation of the compressor 10 needs to be restarted, the discharge of the compressor 10 will occur. Since the pressure states on the suction side and the suction side are balanced, it is sufficient to start the compressor 10 while continuing the operation of the compressor 27, and shift to the capacity addition operation without interrupting the operation of the air conditioner. can do.

As described above, the air conditioner of the present embodiment controls the operation of each compressor by giving priority to the operation of the compressor having a higher operation priority set in advance, based on the air conditioning load on the indoor side. The operation control device 30 and the indoor load detection device for detecting the air conditioning load on the indoor side are provided, and the check valves 38, 39 are provided in the discharge pipes of the compressors 10, 11 other than the compressor 27 having the highest operation priority. Since each is provided, the compressor 27
Even when the operation of the compressors 10 and 11 other than the above is stopped, the backflow of the refrigerant from the compressor 27 that continues the operation is prevented, and the refrigerant is not condensed in the closed container, so that the gas required for the refrigeration cycle It is possible to prevent the quantity from becoming insufficient. Furthermore, since the pressure in the closed container of the compressor at the time of stoppage can be maintained at a substantially low pressure of the refrigeration cycle, when the compressor is additionally operated in response to an increase in indoor load, the second compressor can be quickly operated. It can be started, and comfortable air conditioning can be performed.

Next, a tenth embodiment of the air conditioner according to the present invention will be described with reference to FIG.

FIG. 10 is a refrigeration cycle diagram of the air conditioner in the tenth embodiment of the present invention, and the second embodiment will be described as an example.

In FIG. 10, the difference from the second embodiment is that the operation of each compressor is controlled by giving priority to the operation of the compressor having a high operation priority set in advance based on the air conditioning load on the indoor side. The machine operation control device 30, the indoor load detection device for detecting the air conditioning load on the indoor side, and the check valve 38 installed in the discharge side pipes of the compressors 10 and 11 other than the compressor 27 having the highest operation priority. , 39, bypass circuits 42, 43 for bypassing the upstream and downstream sides of the check valves 38, 39 in the refrigerant flow direction via the on-off valves 40, 41, and the compressor operation control device 30. In addition, when the stop of the compressor is detected, the bypass control device 44 that opens the on-off valve of the bypass circuit of the stopped compressor for a predetermined time is provided.

The operation of the air conditioner configured as described above will be described below. Here, the operation of the tenth embodiment is substantially the same as the operation of the second embodiment, so detailed description will be omitted.

When the indoor load is reduced while the three compressors are in operation, for example, the decompression devices 8b, 8c and 8d are fully closed, the compressors 10 and 11 are stopped, and the compressor 27 is continuously operated. When the capacity control operation is started, the compressor 10,
When the oil level height of the refrigerating machine oil 11 is high, that is, the oil level heights of the three compressors are not well balanced, when the compressors 10 and 11 stop, the check valves 38 and 39
The effect of the discharge pressure of the compressor 27 is
It will not be received inside the sealed container of 11.

Therefore, the excess refrigerating machine oil of the compressors 10 and 11 whose oil surface heights are not sufficiently balanced is supplied to the compressor 27 through the expansion devices 16 and 17, but the excess expansion oil of the expansion devices 16 and 17 is used. Since the pressure difference between the front and the rear is very small, it takes a long time to supply the excess refrigerating machine oil of the compressors 10 and 11 to the compressor 27.

Therefore, in the air conditioner of this embodiment, the bypass circuits 42, 43 for connecting the upstream side and the downstream side of the check valves 38, 39 in the refrigerant flow direction via the open / close valves 40, 41.
And the bypass control device 44 that opens the on-off valves 40 and 41 of the bypass circuits 42 and 43 of the stopped compressors for a predetermined time when the compressors stop, so that the three compressors are operated. The indoor load decreases during the operation, for example, the decompression device 8
When b, 8c, and 8d are fully closed, the compressors 10 and 11 are stopped, and the capacity control operation in which the compressor 27 is continuously operated is started, the oil level of the refrigerating machine oil of the compressors 10 and 11 is increased. Is high, that is, when the compressors 10 and 11 stop in a state in which the oil level heights of the three compressors are not well balanced, the bypass control device 44 causes the bypass controllers 44 to stop at the same time as the compressors 10 and 11 stop. The on-off valves 40 and 41 are opened for a predetermined time.

Therefore, the operation of the on-off valves 40 and 41 causes the influence of the discharge pressure of the compressor 27 to be exerted in the hermetically sealed containers of the compressors 10 and 11 for a predetermined time.
Since the pressure difference around 7 can be sufficiently maintained, the surplus refrigerating machine oil of the compressors 10 and 11 whose oil surface heights are not sufficiently balanced is supplied to the compressor 27 in a short time.

As described above, in the air conditioner of this embodiment, each of the compressors 10 other than the compressor 27 having the highest operation priority,
By-pass circuits 42 and 43 for bypassing the check valves 38 and 39 installed in the discharge side pipe 11 and the upstream and downstream sides of the respective check valves in the refrigerant flow direction via the on-off valves 40 and 41.
And a bypass control device 44 that opens the on-off valves of the bypass circuits 42, 43 of the compressor that have stopped when the compressor operating controller 30 detects that the compressor that was operating has stopped. Therefore, even if the compressor is stopped when the oil level is high, it is possible to supply the excess refrigeration oil of the compressor to other compressors in a short time,
The reliability of refueling the compressor can be improved.

[0151]

Since the air conditioner of the present invention is constructed as described above, it has the following effects.

A plurality of high-pressure chamber type compressors connected in parallel to each other in which a discharge pressure acts in an airtight container, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, and an accumulator are used as a refrigerant flow. While forming a refrigeration cycle by connecting in an annular shape through a passage, one end communicates with each of the hermetically sealed containers at a predetermined height between the oil supply limit oil level and the maximum oil level of each compressor, and the other end. Is connected to the suction side pipes of the compressors, and a collecting section is provided in the middle of both ends, and an oil recovery circuit having a throttle device is provided between the compressors and the collecting section. It is possible to adjust the refrigerating machine oil level in each compressor without being extremely biased not only during the operation of one compressor but also during operation of one compressor, two of them are stopped, or two of them are stopped. it can.

Further, based on the air conditioning load on the indoor side, the compressor operation control device for controlling the operation of each compressor by giving priority to the operation of the compressor having a high preset operation priority, and the air conditioning load on the indoor side are set. An indoor load detection device for detecting, and at least one of a plurality of high-pressure chamber type compressors in which a discharge pressure acts in a closed container is a variable capacity compressor, and each of the compressors is operated. The compressor with the highest operation priority is set as the variable capacity compressor, and the plurality of compressors connected in parallel, the outdoor heat exchanger, the pressure reducing device, and the indoor side are set. A heat exchanger and an accumulator are annularly connected via a refrigerant flow path to form a refrigeration cycle, and one end is between the oil supply limit oil level and the maximum oil level of each compressor other than the variable capacity compressor. At a predetermined height of Through, the other end communicates with the suction side pipe of the variable capacity compressor, and a first oil recovery circuit having a first expansion device in the middle of both ends, and one end has an oil supply limit of the variable capacity compressor It communicates with the inside of the closed container at a predetermined height between the oil level and the maximum oil level, the other end communicates with the suction side pipe of each compressor other than the variable capacity compressor, and in the middle of both ends. Since a collecting section is provided and a second oil recovery circuit having a second expansion device is provided between the suction side piping of each compressor other than the variable capacity compressor and the collecting section, for example, three compressors are provided. Of course, one is running and two are stopped,
Alternatively, even when two units are operated and one unit is stopped, the refrigerating machine oil level in each compressor can be adjusted without being extremely biased. Furthermore, since the excess refrigerating machine oil of other compressors can be preferentially supplied to the variable capacity compressor with the largest fluctuation of the oil level height, the variable surface compressor can reduce the oil level height in a short time. The oil level can be made uniform among a plurality of compressors.

In the second oil recovery circuit, an oil sump tank is provided between the variable capacity compressor and the second expansion device in the middle of the oil recovery path, so that excess refrigerating machine oil is temporarily removed. It has an excellent effect that it can be stored in the oil sump tank, the refrigerating machine oil level is maintained at a predetermined value, and the compression function force is not lowered.

In the oil recovery passage, one end of the pipe connected to the closed container of each compressor is located between the oil supply limit oil level and the maximum oil level of each compressor and inside the closed container of each compressor. Installed at a predetermined height below the oil surface partition plate that is provided above the oil sump and separates the oil in the discharge gas, and one end of the oil recovery passage is projected into each closed container. This prevents the refrigerating machine oil flowing through the wall surface of each compressor closed container from flowing out through the oil recovery path before the refrigerating machine oil accumulates to a predetermined level, and can maintain the specified oil level, which causes the refrigerator oil to run out. It is possible to reliably prevent burning damage to the compressor due to.

Further, a suction main pipe which connects the accumulator and the suction side pipe of each compressor is provided, and the suction side pipe of the compressor having the highest operation priority is connected to the most downstream portion in the refrigerant flow direction of the suction main pipe. Therefore, when some of the multiple compressors are stopped, refrigerating machine oil flowing from the accumulator is prevented from accumulating in the suction side pipe of the stopped compressor, and the stopped compressor is stopped. It is possible to prevent oil compression when restarting.

Further, since the ring-shaped projection is provided on the inner wall surface of the main suction pipe in a direction substantially perpendicular to the flow direction of the refrigerant, the performance of the air conditioner is not affected, and the inside of the main pipe of the suction pipe is not affected. The refrigerating machine oil flowing along the wall surface can be evenly flowed, the imbalance of the refrigerating machine oil amount flowing into each compressor can be reduced, and the difference in the refrigerating machine oil level of each compressor can be reduced.

Further, since the suction main pipe communicating with the accumulator and the agitation tank for agitating the refrigerant and the refrigerating machine oil are provided between the suction side pipe of each compressor, the suction main pipe enters the agitation tank. Since the refrigerant and the refrigerating machine oil that have flown out reach the suction side pipe of the compressor while swirling inside the stirring tank, the amount of refrigerating machine oil that flows into each compressor becomes equal, and there is a difference in the refrigerating machine oil level of each compressor. It can be reduced.

Further, the main suction pipe is located below the connecting position of the airtight container of each compressor and the suction pipe of each compressor, and is installed substantially horizontally, and is branched from the main suction pipe. Even if some compressors of a plurality of compressors are stopped by connecting the compressor up to the connection to the closed container vertically, the suction side of the compressor stopped through the communication pipe. The refrigerating machine oil flowing into the pipe has no refrigerant flow to the stopped compressor, so that no force acts on the refrigerating machine oil from the refrigerant, and the refrigerating machine oil is not drawn to the compressor during the stoppage. Refrigerating machine oil does not collect in the suction side pipe, and there is no problem in liquid compression at the time of starting the stopped compressor.

Further, since check valves are provided in the discharge pipes of the compressors other than the compressor having the highest operation priority, when the operation of the compressors other than the compressor having the highest priority is stopped. However, it prevents the backflow of the refrigerant from the compressor with the highest priority that continues the operation and prevents the refrigerant from condensing in the closed container, so that the amount of gas required for the refrigeration cycle is insufficient. In addition, the pressure inside the airtight container of the compressor at the time of stop can be maintained at a substantially low pressure of the refrigeration cycle, so that the second unit can be promptly operated when the compressor is additionally operated against an increase in indoor load. Can start the compressor of
Comfortable air conditioning can be achieved.

Further, the check valves installed in the discharge side pipes of the compressors other than the compressor having the highest operation priority, and the upstream and downstream sides of the respective check valves in the refrigerant flow direction via the on-off valves. Side bypass circuit and a bypass control device that opens the opening / closing valve of the bypass circuit of the stopped compressor for a predetermined time when it detects that the compressor operating by the compressor is stopped Therefore, even if the compressor is stopped in a state where the oil level is high, the excess refrigerating machine oil of the compressor can be supplied to another compressor in a short time. The reliability regarding refueling can be improved.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a refrigeration cycle diagram of an air conditioner according to a second embodiment of the present invention.

FIG. 3 is a refrigeration cycle diagram of an air conditioner according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a compressor hermetic container of an air conditioner according to a fourth embodiment of the present invention.

FIG. 5 is a refrigeration cycle diagram of an air conditioner according to a fifth embodiment of the present invention.

FIG. 6 is a detailed view of a main part of a suction side pipe of a compressor of an air conditioner according to a sixth embodiment of the present invention.

FIG. 7 is a detailed view of a main part of a suction side pipe of a compressor of an air conditioner according to a seventh embodiment of the present invention.

FIG. 8 is a detailed view of a main part of a suction side pipe of a compressor of an air conditioner according to an eighth embodiment of the present invention.

FIG. 9 is a refrigeration cycle diagram of an air conditioner according to a ninth embodiment of the present invention.

FIG. 10 is a refrigeration cycle diagram of an air conditioner according to a tenth embodiment of the present invention.

FIG. 11 is a refrigeration cycle diagram of a conventional air conditioner.

[Explanation of symbols]

 4 Outdoor heat exchanger 5 Accumulator 8a, 8b, 8c, 8d Pressure reducing device 10, 11, 12 Compressor 13 1st oil recovery path 14 2nd oil recovery path 15 3rd oil recovery path 16, 17, 18 Throttling device 19 Oil recovery collective pipe 20,21,22 Suction side pipe 23,24,25 Oil distribution line 26 Oil recovery circuit 27 Variable capacity compressor 28 First oil recovery circuit 29 Second oil recovery circuit 30 Compressor operation control device 31 Oil Reservoir tank 33 Oil surface partition plate 34 Compressor closed container 35 Oil sump 36 Protrusion 37 Stirring tank 38,39 Check valve 40,41 Open / close valve 42,43 Bypass circuit 44 Bypass controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunji Moriwaki 3-22 Takaidahondori, Higashi-Osaka City, Osaka Prefecture Matsushita Refrigerator Co., Ltd. (72) Hiroaki Eguchi 3-22 Takaidahondori, Higashi-Osaka, Osaka Matsushita Refrigerator Co., Ltd. (72) Inventor Junji Hayashi 3-22 Takaidahondori, Higashi-Osaka City, Osaka Prefecture Matsushita Refrigerator Co., Ltd. (72) Inventor Akihiro Yabushita 3-22 Takaidamoto-dori, East Osaka City, Osaka Matsushita Refrigerator Co., Ltd. (72) Inventor Takayuki Takaya 3-22 Takaidahondori, Higashi-Osaka, Osaka Prefecture Matsushita Refrigerator Co., Ltd. (72) Inventor Tetsuhide Kuramoto 3-22, Takaidahondori, East Osaka, Osaka Matsushita Refrigerator Co., Ltd. Within

Claims (10)

[Claims] 1. A compressor in which a plurality of units are connected in parallel by a high-pressure chamber system in which a discharge pressure acts in a closed container, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, and an accumulator. To form a refrigeration cycle by connecting them annularly through a refrigerant flow path, and one end communicates with each of the hermetically sealed containers at a predetermined height between the oil supply limit oil level and the maximum oil level of each compressor. And an oil recovery circuit in which the other end communicates with the suction side pipe of each compressor, a collecting section is provided in the middle of both ends, and a throttle device is provided between each compressor and the collecting section. Air conditioner. 2. A compressor operation control device for controlling the operation of each compressor by giving priority to the operation of a compressor having a high operation priority set in advance based on the indoor air conditioning load, and an indoor air conditioning load. An indoor load detection device for detecting, and at least one of a plurality of high-pressure chamber type compressors in which a discharge pressure acts in a closed container is a variable capacity compressor, and the operation priority is the highest. A high compressor as a variable capacity compressor, the plurality of compressors connected in parallel, an outdoor heat exchanger, a decompressor, an indoor heat exchanger, and an accumulator through a refrigerant flow path. To form a refrigeration cycle by connecting in an annular manner with one end in each of the hermetically sealed containers at a predetermined height between the oil supply limit oil level and the maximum oil level of each compressor other than the variable capacity compressor. Communication, the other end is the suction of the variable capacity compressor A first oil recovery circuit communicating with the side pipe and having a first expansion device in the middle of both ends; and
One end communicates with the variable capacity compressor at a predetermined height between the oil supply limit oil level and the maximum oil level in the closed container, and the other end sucks in a compressor other than the variable capacity compressor. A second oil that communicates with the side pipe and has a collecting portion in the middle of both ends, and has a second expansion device between the suction side pipe of each compressor other than the variable capacity compressor and the collecting portion. An air conditioner equipped with a recovery circuit. 3. The second oil recovery circuit, further comprising an oil sump tank between the variable capacity compressor and the collecting section.
Air conditioner described. 4. In the oil recovery circuit, one end of a pipe connected to the closed container of each compressor is between the oil supply limit oil level and the maximum oil level of each compressor, and the closed container of each compressor. It is installed at a predetermined height below the oil surface partition plate that is provided above the oil sump inside and separates oil from the discharge gas, and one end of the oil recovery circuit is projected into each closed container. The air conditioner according to any one of claims 1 to 3. 5. A suction main pipe that connects the accumulator and the suction side pipe of each compressor is provided, and the suction side pipe of the compressor having the highest operation priority is the most downstream part in the refrigerant flow direction of the suction main pipe. The air conditioner according to any one of claims 2 to 4, which is connected to the air conditioner. 6. The projection according to claim 1, wherein a projection is provided on a pipe inner wall surface of the suction main pipe at an upstream portion in a refrigerant flow direction with respect to a connecting portion between the suction main pipe and a suction side pipe of each compressor. The air conditioner according to any one. 7. A stirring tank for stirring the refrigerant and oil in the suction main pipe is provided between the suction main pipe and the suction side pipe of each compressor, and one end of the suction main pipe is connected to the stirring tank. 5. The connection is made in a substantially tangential direction of a side wall surface and in a substantially horizontal direction, and one end of a suction side pipe of each compressor is connected from an upper surface of the stirring tank. Air conditioner. 8. The main suction pipe is below the connection position between the closed container of each compressor and the suction pipe of each compressor, and
Installed in a substantially horizontal direction, at one end of the suction side piping of each of the compressors on the suction main piping side, a pipe extending portion extending upward in a direction substantially perpendicular to the suction main piping is provided, and an oil recovery circuit One end of each compressor on the suction side pipe side is connected to the pipe extending part, and the connecting part is below the connection position between the closed container of each compressor and the suction side pipe of each compressor. The air conditioner according to any one of claims 1 to 7, which is arranged as described above. 9. A compressor operation control device for controlling the operation of each compressor by giving priority to the operation of a compressor having a high operation priority set in advance based on the air conditioning load on the indoor side, and an air conditioning load on the indoor side. The air conditioner according to any one of claims 2 to 8, further comprising: an indoor load detection device for detecting; and a check valve installed in a discharge side pipe of each compressor other than the compressor having the highest operation priority. . 10. A compressor operation control device for controlling the operation of each compressor by giving priority to the operation of a compressor having a high operation priority set in advance on the basis of the air conditioning load on the indoor side, and an air conditioning load on the indoor side. An indoor load detection device for detecting, a check valve installed in the discharge side pipe of each compressor other than the compressor with the highest operation priority, and an upstream side in the refrigerant flow direction of each check valve via an on-off valve. A bypass circuit for bypassing the downstream side and the downstream side, and when the compressor operating by the compressor operation control device detects that the compressor has stopped, the on-off valve of the bypass circuit of the stopped compressor is opened for a predetermined time. The air conditioner according to any one of claims 2 to 9, further comprising a bypass control device.